Pumping apparatus



March 6, 1956 w HILL 2,737,119

PUMPING APPARATUS Filed May 25, 1951 INVENTOR United States Patent PUMPING APPARATUS Robert H. Hill, Fort Wayne, Ind., assignor, by mesne assignments, to Perfect Circle Corporation, Hagerst'own, Ind., a corporation of Indiana Application May 23, 1951, Serial No. 227,845

2 Claims. (Cl. 103-3) This invention relates generally to pumping apparatus and more particularly to a novel reversible pumping arrarigement for use in oil wells or the like.

In certain types of low pressure oil wells it is necessary to remove the oil by pumping the same out of the well through suitable tubing. The customary pumping arrangement in such cases comprises a reciprocating pump located adjacent the bottom of the well casing and connected to the tubing. The pump is operated by an elongated sucker rod extending upwardly, through the tubing and the well casing to an actuating mechanism located above ground. In many instances the lower or intake end of the tubing is fitted with a screen or strainer to prevent solid material from being drawn into the pump alongwith the oil.

It is a common experience in oil wells, particularly wells of the character described above, that the sand strata or other producing formations at the bottom of the well.

eventually become clogged or obstructed to such an extent that the yield from the well becomes too low to warrant further operation of the well. In some cases-the well is abandoned, but in many instances an attempt is made to clean the well by forcing water, acid, or other suitable purging material into the producing formation whereby to remove the obstructions in the formation and restore the flow of oil to a profitable level. In some cases the purging fluid may even contain added solid material for the purpose of further expanding and enlarging the producing formation. Heretofore, in cleaning a well of this type it has been necessary to remove the reciprocating pump together with the sucker rod and tubing in' order to permit the insertion of a temporary pipe into the well casing for injecting the cleaning fluid into the well. Upon completion of the cleaning operation, the temporary pipe must be removed and the reciprocating pump with its sucker rod and tubing must be reinstalled before the production of oil can be resumed. Obviously, this manner of cleaning an oil well is cumbersome and time consuming and involves substantial expense. cases where the production of the well at best is small, it is questionable whether the expense of cleaning the well is warranted.

Accordingly, the general object of my invention is to provide novel means for maintaining a well in free flow-- ing condition at relatively small expense and in a highly convenient and rapid manner.

A further object of the invention is to provide novel reversible pumping apparatus for a well by means of which fluid may alternately be pumped out of the well and returned to the well under pressure to effect cleaning of the well by removal of obstructions therein.

Another object of the invention is to provide a novelmeans for cleaning a well by injection of fluid info the producing formation under high pressures such that in many cases of slow flowing wells the formation isnot only purged but is fractured and broken down wherebyto increase the normal flow from the well.

Still another object of. theinvention is to provide pump- In fact, in many' Z,737,l l9 Fatented Mar. 6, 1956 ing apparatus for a well including a novel combination of a reversible motor and reversible pump for pumping fluid out of the well or injecting fluid under pressure into the well as desired.

Other objects and advantages of the invention will become apparent from the subsequent detailed description taken in connection with the accompanying drawing wherein:

Fig. 1 is an elevational view on a reduced scale of apumping apparatus embodying the features of my inven-- tion and showing the apparatus in position in a well casing; and

Fig. 2 is a vertical sectional view on an enlarged scale taken along the line 22 of Fig. 1. 7

Referring first to Fig. 1, the fragmentary lower portionof an oil well casing 6 is shown and the surrounding. earthformation is indicated diagrammatically atv 7. It will be understood that the casing 6 extends in the usual manner from the ground level to the bottom of the well althoughneither of the extreme ends of the casing are illustratedin the drawing. The pumping apparatus comprising my from the top of the pumping apparatusthrough the well caslng to the ground level. Suitable electrical conductors- 11 extend from the ground level downwardly through the casing 6 to the motor section A for operating the latter.

7 During production, the reversible motor section A is operated so that the reversible pump section B draws oil from the bottom of the well casing through the inlet 8 and the valve section C and discharges the oil through suitable passageways in the motor section A to the outlet pipe 9 which is connected to a tank or other storage facilities at the ground level. When the producing formation and/or the intake 8 become clogged or obstructed to an objectionable degree, as indicated by a low volume of oil issuing from the well, the motor is reversed and the pump is thereby operated in reverse fashion so that oil or other suitable purging material is pumped downwardly through the pipe 9 and is discharged from the intake 8 under pressure. In order to insure that the oil or other material is forcibly injected into the adjacent producing formation at the bottom of the well, a portion of the pump section B is fitted with a packer 12 of a type adapted to resist upward pressure. 7

in the embodiment shown in the drawing, the packer 12 is of a conventional type comprising an axially come pressible rubber sleeve. The rubber sleeve is secured around the upper portion of the pump casing, and as the apparatus is initially installed in the well casing the rubber sleeve is retracted as seen in dotted lines in Fig. 1 However, by means of a telescoping action, well known in the packer art, slidable sections of the pump casing are shifted after the apparatus is in place in the well and the rubber sleeve is compressed and bulged outwardly into tight fitting sealed relation with the inside of the well casing 6 as shown in full lines in Fig. 1. In this manner, it will be understood that the packer 12 effectively segregates the lower portion of the well so as to define a reservoir space between the packer and the bottom of the Well. It is an importantfeature of my invention that the rubber sleeve comprising the packer 12 is disposed only around the upper portion of the pump so that the lower end of the pump extends below the packer into the reservoir space. Thus, when oil or other purging material .is pumped downwardly into the well under pressure, the reservoir space is sealed at its upper end by the packer 12 3 and the oil is therefore readily forced under high pressure into the obstructed producing formation or strata for purging and cleaning the same. At the same time, the perforated or slotted intake 8 is also cleaned and flushed out.

When an oil well is equipped with a pumping apparatus as described above in connection with Fig. 1, the desired free flowing conditions in the well may, if desired, be maintained by periodically reversing the flow of oil on a predetermined cycle so that the intake and the produc ing strata of the well are subjected to frequent back flow of oil for cleaning and flushing purposes. Such intermittent operation may obviously be effected manually, but it is possible to utilize an automatic means such as a time controller device in the electrical circuit for the motor section A so that the Well is automatically cleaned on a predetermined time schedule. Other control schemes may also be employed, for example, reversal of the motor for pressurizing of the well may be arranged to occur in response to a decrease in the pressure or flow rate of the effluent oil below a predetermined level.

The purpose of the valve section C is to maintain the head of oil in the pumping apparatus and the outlet tubing 9 during a period in which the direction of oil flow is being reversed or in which the motor is stopped for any reason. However, the details of the valve section C do not constitute a part of the present invention and accordingly this portion of the apparatus need not be described further.

Referring now to Fig. 2, there is shown an enlarged view of the lower end of the motor section A and the upper end of the pump section B together with the driving connections therebetween. My invention is characterized by the use of a reversible pump of the positive displacement type in which there is an elongated rotary pumping member having driving connections with the motor of the device for operation in either a clockwise or counterclockwise direction. Dependent upon its direction of rotation, the rotary member of the pump exerts an axial or endwise thrust either upwardly or downwardly in a direction opposite to the direction of oil flow.

More particularly, as will be described hereinafter in detail, my invention contemplates the use of the progressing cavity type pump known commercially as the Moyno pump and comprising a female helical member which constitutes the stator of the pump and a male helical member mounted in the female member and constituting the rotor of the pump. The outer member or stator is provided with one helical thread more than the inner member or rotor, and the two members are so arranged and shaped that every thread of the rotor is constantly in contact with the stator in any transverse section through the pump. This relation of the rotor and stator is such that a plurality of closed spaces or cavities are defined between the two members because of the difference in the number of threads on each member. When the rotor is rotated relative to the stator, the cavities or spaces between the members are displaced in a longitudinal direction with the result that a fluid material can be axially transported between the two members to obtain the desired pumping effect. Reference is made to U. S. Patents Nos. 1,892,217 and 2,028,407 for a detailed consideration of the theory and operation of the progressing cavity type of pump.

As will hereinafter appear, I have found that a reversible pump of the progressing cavity type is particularly suitable for use in the pumping apparatus of the present invention because it is capable of generating very high pressures and because sand or other solids in the fluid being pumped do not cause undue wear or operating difiiculties in a pump of this type. However, in order to utilize such a pump for my purposes it is necessary to provide suitable thrust bearing means for receiving the thrust reaction when the pump is operated in either direction of rotation. Accordingly, the combination of a reversible motor with a reversible pump of the above-described type together with a dual thrust bearing means constitutes one of the primary features of the present invention.

In Fig. 2 the rotor shaft of the motor is indicated at 16, the lower end of the shaft extending through an end plate or member 17 which is secured at the lower end of an innermost tubular shell 18 by means of a spring ring 19. The motor is surrounded by an outermost tubular casing or shell 20, and the inner shell 18 has a plurality of elongated grooves 21 whereby to define a plurality of axially extending fluid passageways. A suitable shaft seal 22 is provided in the end plate 17 around the rotor shaft 16. The outer motor casing 20 is threadedly connected at its lower end to a coupling member 23 having a plurality of sockets 24 adapted to receive the lugs of a spanner wrench. Intermediate the motor casing 18 and the coupling member 23 and in endwise abutment therewith is a cylindrical spacer element 26 having a plurality of endwise slots 27 at its upper end for the purpose described hereinafter.

The casing of the pump section B comprises a tubular member 28 which is secured to the coupling member 23 by means of a threaded connector or collar 29. An elongated cup-shaped pump support 30 is mounted at the lower end of the coupling 23 by means of a spring ring 31 and has threadedly secured in its bottom wall a bushing 32 which is in turn threadedly connected to a tubular conduit 33 comprising the outer portion of the pump stator. The interior of the tube 33 is provided with a helical lining 34, preferably of rubber, which constitutes the female helical member hereinbefore referred to. An elongated male helical member or rotor 36 is operatively disposed within the helical liner 34 of the pump stator for rotation in either direction, an axial thrust or reaction being exerted by the rotor 36 in a direction opposite to the direction of oil flow as hereinbefore described.

A driving connection in the form of a universal joint extends between the lower end of the rotor shaft 16 and the upper end of the helical rotor 36 in order. to compensate for misalignment between the rotating parts and for facilitating assembly and installation of the apparatus. This universal connection, in the embodiment shown by way of illustration in the drawing, comprises an elongated connector shaft 37 extending through the coupling member 23 and having spherical or ball-shaped end portions 38 which are operatively attached in pivotal relation to the adjacent ends of the rotor shaft 16 and the rotor 36 of the motor and pump, respectively. The pivotal connecting means comprises a pair of cup-shaped shaft adaptors 39 having the end portions of the rotor shaft 16 and the rotor 36 extending therethrough and keyed thereto. A retainer nut 41 is threaded onto the ends of the rotor shaft 16 and the rotor 36 for retaining the adaptors 39 in place. Each of the spherical end portions 38 of the connector shaft 37 is received within one of the adaptor members 39 and is connected to the latter by means of a transverse pivot pin 42 extending through a bore 43 in the end portion 38 and also in a pair of diametrically located apertures 44 in the skirt portion of the adaptor 39. Each pin 42 is retained in place by means of a cap member 45 which fits over the inner end of the adaptor 39 and engages the opposite ends of the pin 42. In addition to the pivotal connection of the connector shaft 37 at each end of the pivot pins 42, it will also be noted that the transverse bore 43 in each of the end portions 38 of the connector shaft 37 tapers outwardly from its center to the opposite ends thereof. As a result, the pins 42 can also undergo a certain degree of transverse rocking movement in a plane at right angles to the plane of pivotal movement of the shaft 37 relative to the pins 42 thereby permitting additional automatic adjustment of the driving connection between the motor and the pump.

In the operation of the device during a production period, oil is pumped upwardly between the stator 34 and the rotor 36, into the space in the pump support 30, through the coupling member 23', and thence through! the slots 27 in the spacer 26 into the passageways 21 sur' rounding the motor, as indicated by the double-headed arrows in Fig. 2 of the drawing. Although not shown in the drawing, it will be understood that the oil eventually passes from the passageways 21 into the outlet conduit 9 and is ultimately discharged at the ground level. During a cleaning or reverse flow period, oil passes downwardly from the motor section and into the pumping mechanism for ultimate discharge under pressure through the intake 8.

It will be evident that during a production period when oil is being pumped upwardly to the ground level, there will be a downward thrust or reaction exerted by the pump rotor 36 which is transmitted through the universal connection to the rotor shaft 16 of the motor. Similarly, when the well is being pressurized by reverse flow, there will be an upward thrust or reaction against the rotor shaft 16 as a result of the downward flow of oil under pressure. In either case, the total pressures involved are the result not only of the discharge pressure created by the pump but also of the head of oil above the pump which, in the case of a deep Well, may be substantial. In order to receive these oppositely acting thrust reactions, I provide a double thrust bearing consisting of an upper bearing unit 46 and a lower bearing unit 47, the two units being held in side-to-side relation by means of a bearing retainer 48 around the lower end portion of the rotor shaft means. In this instance the rotor shaft means consists only of the shaft 16 but it will be understood that a two part construction employing an extension shaft connected to the main rotor shaft could also be used when necessary and in such case the double thrust bearing means will preferably be provided adjacent the lower end of the extension shaft.

Each of the bearing units 46 and 47 comprises a pair of inner and outer annular races between which are mounted a plurality of balls 49 and 51, respectively. The inner races of each bearing unit are formed with suitable annular grooves 52 in which the balls are seated. The outer races of each of the bearing units are formed with non-symmetrical shoulder portions for resisting axial thrust or reaction in a single direction, either upwardly or downwardly. Thus, the upper bearing unit 46 has a lower annular shoulder 53 which coacts with the balls 49 to resist the downward thrust of the rotor shaft 16 during the period when the pump is pumping oil upwardly out of the well. Similarly, the lower bearing unit 47 is formed with an upper annular shoulder portion 54 which coacts with the balls 51 whereby to resist the upward thrust on the rotor shaft 16 during the time when the pump is pumping oil downwardly into the well under pressure. The bearing units 46 and 47 are retained against axial movement by abutment of the lower bearing unit 47 against an upstanding flange portion 56 on the end plate 17 and by engagement of the upper bearing unit 46 with a shoulder 57 on the retainer 48. It will be understood that suitable lubricating means is also provided for the bearings 46 and 47.

It will be evident from the foregoing description that the use of a reversible pump of the type specified, wherein an axial thrust is exerted in opposite directions depending upon the direction of rotation of the pump, requires special provision for absorbing the thrust reactions for both directions of rotation of the pump mechanism. My invention meets this problem and makes it feasible to utilize a progressing cavity positive displacement type of pump as a reversible pump by the provision of the dual thrust bearing arrangement. As described above, one of the thrust bearing units is especially designed to receive the axial thrust of the rotor shaft of the motor during operation of the pump in one direction and the other thrust. bearing unit. receives the axial thrust when the pump is operated in. the reverse. direction;

It will be seen that my invention provides a hi fly advantageous combination of reversible motor and pump for realizing alternate production and pressurizing of an oil well in a very convenient and reliable manner and at relatively low' cost. Pumping apparatus of the character described. is readily adapted for more or less permanent installation in an oil well in the sense that it is unnecessary to remove the apparatus or the tubing in order to effect cleaning of the Well. Moreover, the positive displacement progressing cavity type of pump, as herein described, is particularly adapted for the present purpose because of its ability to create tremendous discharge pressures while at the same time being relatively unaffected by the presence in the oil of extraneous solid particles, gases, or vapors. In fact, under certain conditions the use of my device may result in a substantial increase in the production of a well because the extremely high fluid pressures created by a pump of this type may effect fracture or disruption of the earth formation in addition to the removal of obstructions or accumulations of solid material from the producing strata. It will also be seen that because of the elongated character of a pump of this type it is readily adapted for insertion into an oil Well casing in the manner described.

Although the invention has been described in connection with a specific structural embodiment thereof, it will be understood that various modifications and equivaient structures may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. Pumping apparatus for an oil well comprising a reversible motor having a rotor shaft and an elongated tubular casing surrounding said motor, a reversible pump disposed below said motor and having an elongated tubular pump casing, a coupling member having its upper end received within the lower end of said motor casing and threadedly attached thereto, a cylindrical spacer within said motor casing and in engagement at its upper end with the motor and at its lower end with said coupling member, a collar surrounding the lower end of said coupling member and the upper end of said pump casing and threadedly connected thereto, a cupshaped pump support attached adjacent its upper end to the lower end of said coupling member and extending downwardly through said collar into said pump casing, an elongated pump stator within said pump casing and connected at its upper end to the lower end of said support, an elongated pump rotor operatively disposed in said stator in pumping relation therewith and extending at its upper end into said cup-shaped support, and elongated driving connector means extending between the adjacent ends of said rotor shaft and said pump rotor and operatively connected thereto.

2. Pumping apparatus for an oil well comprising a reversible motor having a rotor shaft and an elongated tubular motor casing surrounding said motor, a reversible pump disposed below said motor and having an elongated tubular pump casing, coupling means having its upper end received within the lower end of said motor casing and threadedly attached thereto, a cylinder spacer within said motor casing and in engagement at its upper end with the motor and at its lower end with said coupling means, said coupling means being connected at its lower end to the upper end of said pump casing and providing a generally cup shaped pump support therein, an elongated pump stator within said pump casing and rigidly connected at its upper end to said pump support, an elongated pump rotor operatively disposed in said stator in pumping relation therewith and projecting at its upper end into said cup-shaped support, and elongated driving connector means extending between thereto.

References Cited in the file of this patent UNITED STATES PATENTS Deming Nov. 20, 1934 8 Johnsen July 30, 1940 Downs Jan. 6, 1942 Crites Sept. 28, 1943 Arutunofi June 5, 1945 Laurnan Oct. 12, 1948 Byram Oct. 31, 1950 Teetor Dec. 25, 1951 

